Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A collimating light emitting device comprises a patterned optical layer
able to redirect divergent light to light beam with uniform direction
without utilizing external lenses thereby decreasing the size. The
collimating light emitting device of the present invention may be
utilized as a micro array projection device. The patterned optical layer
may also be utilized in a single-die light-emitting device, thereby
enhancing collimation. The manufacturing methods of the collimating light
emitting device are also presented.

Claims:

1. A manufacturing method of a collimating light emitting device
comprising: providing a carrier board; disposing a buffer layer on said
carrier board; forming a patterned optical layer on said buffer layer,
wherein said patterned optical layer exposes a part of said buffer layer;
forming an epitaxial layer to cover said exposed buffer layer and said
patterned optical layer by means of a procedure of epitaxy of lateral
overgrowth (ELOG); forming a first conductivity type layer on said
epitaxial layer; forming an active layer on said first conductivity type
layer; forming a second conductivity type layer on said active layer;
disposing a first electrode layer on said second conductivity type layer;
and disposing a second electrode layer either below said buffer layer or
on said first conductivity type layer, wherein a procedure of removing
said carrier board is performed before disposing said second electrode
layer below said buffer layer.

3. The manufacturing method according to claim 2, wherein said first
electrode layer comprises a patterned electrode covering a part of said
second conductivity type layer; and said second electrode layer comprises
a conducting substrate entirely covering the lower surface of said buffer
layer.

4. The manufacturing method according to claim 2, wherein said procedure
of removing said carrier board is followed by: disposing said second
electrode layer, wherein said second electrode layer comprises a
conducting substrate entirely covering the lower surface of said buffer
layer; cutting through said second conductivity type layer, said active
layer, said first conductivity type layer, said epitaxial layer, said
patterned optical layer and said buffer layer without cutting through
said second electrode layer so as to form a plurality of units configured
in array; and disposing said first electrode layer, wherein said first
electrode layer comprises a plurality of patterned electrodes disposed on
said second conductivity type layer of each said unit, wherein said first
electrode layer exposes a part of said second conductivity type layer.

6. The manufacturing method according to claim 5, wherein said first
electrode layer comprises a conducting substrate entirely covering said
second conductivity type layer; and said second electrode layer comprises
a patterned electrode covering a part of the lower surface of said buffer
layer.

7. The manufacturing method according to claim 5, wherein disposing said
first electrode layer is followed by: removing said carrier board,
wherein said first electrode layer comprises a conducting substrate
entirely covering said second conductivity type layer; cutting through
said buffer layer, said patterned optical layer, said epitaxial layer,
said first conductivity type layer, said active layer and said second
conductivity type layer without cutting through said first electrode
layer, so as to form a plurality of units configured in array; and
disposing said second electrode layer, wherein said second electrode
layer comprises a plurality of patterned electrodes disposed below said
buffer layer of each said unit, wherein said second electrode layer
exposes a part of said buffer layer.

8. The manufacturing method according to claim 1, further comprising
forming a transparent conducting layer between said first electrode layer
and said second conductivity type layer.

9. The manufacturing method according to claim 1, further comprising
forming a transparent conducting layer between said second electrode
layer and said buffer layer.

11. The manufacturing method according to claim 1, wherein said first
conductivity type layer comprises an n-type III-V semiconductor material;
and said second conductivity type layer comprises a p-type III-V
semiconductor material.

12. The manufacturing method according to claim 1, wherein said first
conductivity type layer comprises a p-type III-V semiconductor material;
and said second conductivity type layer comprises a n-type III-V
semiconductor material.

13. A collimating light emitting device comprising: a buffer layer; a
patterned optical layer, disposed on said buffer layer, wherein said
patterned optical layer exposes a part of said buffer layer; an epitaxial
layer, covering exposed said buffer layer and said patterned optical
layer; a first conductivity type layer, disposed on said epitaxial layer;
an active layer, disposed on said first conductivity type layer; a second
conductivity type layer, disposed on said active layer; a first electrode
layer, disposed on said second conductivity type layer; and a second
electrode layer, disposed either below said buffer layer or on said first
conductivity type layer.

15. The collimating light emitting device according to claim 14, wherein
said first electrode layer comprises a patterned first electrode covering
a part of said second conductivity type layer; and said second electrode
layer comprises a conducting substrate entirely covering the lower
surface of said buffer layer.

16. The collimating light emitting device according to claim 14, further
comprising: a trench, penetrating said second conductivity type layer,
said active layer, said first conductivity type layer, said epitaxial
layer, said patterned optical layer and said buffer layer without
penetrating said second electrode layer, wherein said trench defines a
plurality of units configured in array, wherein said first electrode
layer comprises a plurality of patterned first electrodes disposed on
said second conductivity type layer of each said unit, wherein said first
electrode layer exposes a part of said second conductivity type layer,
and said second electrode layer comprises a conducting substrate entirely
covering the lower surface of said buffer layer.

18. The collimating light emitting device according to claim 17, wherein
said first electrode layer comprises a conducting substrate entirely
covering said second conductivity type layer; and said second electrode
layer comprises a patterned second electrode covering a part of the lower
surface of said buffer layer.

19. The collimating light emitting device according to claim 17, further
comprising: a trench, penetrating said buffer layer, said patterned
optical layer, said epitaxial layer, said first conductivity type layer,
said active layer and said second conductivity type layer and without
penetrating said first electrode layer, wherein said trench defines a
plurality of units configured in array, wherein said first electrode
layer comprises a conducting substrate entirely covering said second
conductivity type layer, and said second electrode layer comprises a
plurality of patterned second electrodes disposed on said buffer layer of
each said unit, wherein said second electrode layer exposes a part of
said buffer layer.

20. The collimating light emitting device according to claim 13, further
comprising a transparent conducting layer disposed between said first
electrode layer and said second conductivity type layer.

21. The collimating light emitting device according to claim 13, further
comprising further comprising a transparent conducting layer disposed
between said second electrode layer and said buffer layer.

Description:

[0002] The present invention relates to a light emitting device and
manufacturing method thereof, and more particularly to a light emitting
device emitting collimating light and manufacturing method thereof.

[0003] 2. Description of the Prior Art

[0004] In the field of image display, cost reduction, weight reduction and
miniaturization are developing trends for both projection devices and
display devices. A conventional projection device is consisted of a light
source using LED and a plurality of micro-lenses. Although projecting
efficiency of the projection device is thus improved, it takes a quite
number of lenses to be disposed at the light path of the light emitting
diode so as to emit light with good collimation. The conventional
projection device is limited by the volume of the lenses itself and the
spacing between each lens for miniaturization. Therefore, there have been
increasing demands for developing a collimating light emitting device
with compact size and good performance.

SUMMARY OF THE INVENTION

[0005] The present invention is directed to a collimating light emitting
device and manufacturing method thereof, which comprises a patterned
optical layer able to redirect divergent light to a light beam with
uniform direction without utilizing external lenses thereby decreasing
the size. The collimating light emitting device of the present invention
may be utilized as a micro array projection device.

[0006] According to an embodiment, a manufacturing method of a collimating
light emitting device comprises providing a carrier board; disposing an
buffer layer on the carrier board; forming a patterned optical layer on
the buffer layer, wherein the patterned optical layer exposes a part of
the buffer layer; forming an epitaxial layer to cover exposed the buffer
layer and the patterned optical layer by using an procedure of epitaxy of
lateral overgrowth (ELOG); forming a first conductivity type layer on the
epitaxial layer; forming an active layer on the first conductivity type
layer; forming a second conductivity type layer on the active layer;
disposing a first electrode layer on the second conductivity type layer
and disposing a second electrode layer either below the buffer layer or
on the first conductivity type layer, wherein a procedure of removing the
carrier board is performed before disposing the second electrode layer
below the buffer layer.

[0007] According to an embodiment, a collimating light emitting device
comprises a buffer layer, a patterned optical layer, an epitaxial layer a
first conductivity type layer, an active layer, a second conductivity
type layer, a first electrode layer and a second electrode layer. The
patterned optical layer is disposed on the buffer layer, wherein the
patterned optical layer exposes a part of the buffer layer. The epitaxial
layer covers exposed buffer layer and patterned optical layer. The first
conductivity type layer is disposed on the epitaxial layer. The active
layer is disposed on the first conductivity type layer. The second
conductivity type layer is disposed on the active layer. The first
electrode layer is disposed on the second conductivity type layer. The
second electrode layer is disposed either below the buffer layer or on
the first conductivity type layer.

[0008] The objective, technologies, features and advantages of the present
invention will become more apparent from the following description in
conjunction with the accompanying drawings, wherein certain embodiments
of the present invention are set forth by way of illustration and
examples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office upon
request and payment of the necessary fee.

[0010] The foregoing aspects and many of the accompanying advantages of
this invention will become more readily appreciated as the same becomes
better understood by reference to the following detailed descriptions,
when taken in conjunction with the accompanying drawings, wherein:

[0011] FIG. 1 is a manufacturing process flow of a collimating light
emitting device according to an embodiment of the present invention;

[0012]FIG. 2A to FIG. 2D are schematic cross-sectional views illustrating
the manufacturing process flow of the collimating light emitting device
according to the embodiment of the present invention;

[0013] FIG. 3A and FIG. 3B are respectively schematic cross-sectional view
and plan view illustrating the patterned optical layer of the collimating
light emitting device according to one embodiment of the present
invention;

[0014] FIG. 3C and FIG. 3D are respectively schematic cross-sectional view
and plan view illustrating the patterned optical layer of the collimating
light emitting device according to another embodiment of the present
invention;

[0015] FIG. 4 is a schematic diagram illustrating the collimating light
emitting device according to another embodiment of the present invention;

[0016] FIG. 5A is a schematic diagram illustrating the collimating light
emitting device according to another embodiment of the present invention,
FIG. 5B a schematic diagram rotating the schematic diagram in FIG. 5A for
180 degrees clockwise;

[0017] FIG. 6 is a manufacturing process flow of a collimating light
emitting device according to another embodiment of the present invention;

[0018] FIG. 7A to FIG. 7E are schematic cross-sectional views illustrating
the manufacturing process flow of the collimating light emitting device
according to the embodiment of the present invention;

[0019] FIG. 8A is a schematic diagram illustrating a collimating light
emitting device according to another embodiment of the present invention;

[0020] FIG. 8B is a schematic diagram illustrating a collimating light
emitting device according to another embodiment of the present invention;

[0021] FIG. 9 is a manufacturing process flow of a collimating light
emitting device according to another embodiment of the present invention;

[0022] FIG. 10A to FIG. 10B are schematic cross-sectional views
illustrating the manufacturing process flow of the collimating light
emitting device according to the embodiment of the present invention;

[0023]FIG. 11 is a schematic diagram illustrating a collimating light
emitting device according to another embodiment of the present invention;
and

[0024] FIGS. 12 and 13 are simulation diagrams of light field
distribution.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025] Referring to FIG. 1 and FIG. 2A to FIG. 2D simultaneously, FIG. 1
is a flow diagram illustrating a manufacturing process (Step S11 through
Step S19) of a collimating light emitting device according to an
embodiment of the present invention. FIG. 2A to FIG. 2D are schematic
cross-sectional views illustrating the manufacturing process flow of the
collimating light emitting device according to the embodiment of the
present invention. FIG. 2A is referred as Step S11 to Step S13 in FIG. 1.
At Step S11, a carrier board 21 is provided, and the carrier board 21 may
be made of sapphire, SiC, Si, GaAs, LiAlO2, LiGaO2 or organic
materials. A buffer layer 22 is disposed on the carrier board 21 at Step
S12, wherein the buffer layer may comprise undoped III-V semiconductor
material. In one embodiment of the present invention, the buffer layer 22
may comprise GaN. A patterned optical layer 23 is formed on the buffer
layer 22 at Step S13, wherein the patterned optical layer 23 exposes a
part of the buffer layer 22. Regarding to Step S13, the patterned optical
layer 23 material disposed on the buffer layer 22 may be achieved by
using a sputtering process, an evaporation process, a chemical vapor
deposition, a chemical liquid deposition, a chemical vapor epitaxy or a
chemical liquid epitaxy, and the optical layer 23 is then patterned by
means of photolithography or laser etching. The patterned optical layer
23 may be made of TiO2, Ta2O5, Nb2O5, CeO2,
ZnS, ZnO, SiO2 or MgF2.

[0026] In one embodiment of the present invention as shown in FIG. 2A to
FIG. 2D, the patterned optical layer 23 may be, but not limited to be,
configured in a plurality of triangle units, the shape of units in the
patterned optical layer 23 may include triangle, rectangle, square, arc,
trapezoid or combinations thereof. Please referring to FIG. 3A to FIG. 3D
simultaneously, FIG. 3A and FIG. 3B are respectively a cross-sectional
view and a plan view illustrating the patterned optical layer 23 of the
collimating light emitting device according to one embodiment of the
present invention; FIG. 3C and FIG. 3D are respectively a cross-sectional
view and a plan view illustrating the patterned optical layer 23 of the
collimating light emitting device according to another embodiment of the
present invention. As shown in FIG. 3A and FIG. 3B, the patterned optical
layer 23 comprises a plurality of triangle units configured in a
plurality of concentric squares. In the embodiment shown in FIG. 3C and
FIG. 3D, the patterned optical layer 23 comprises a plurality of
rectangle units configured in a plurality of concentric circles. The
patterned optical layer 23 comprises a Fresnel optical structure capable
of changing the angle of light reaching to the patterned optical layer
23, so as to provide collimating light. The patterned optical layer 23
may comprise a reflective Fresnel optical layer or a transmissive Fresnel
optical layer. In the embodiment shown in FIG. 2A, the patterned optical
layer 23 may be a reflective Fresnel optical layer.

[0027] Referring to FIG. 2B, FIG. 2B is referred to Step S14 to Step S17
in FIG. 1. At Step S14, an epitaxial layer 24 is formed and covers the
exposed buffer layer 22 and patterned optical layer 23 by an epitaxy of
lateral overgrowth (ELOG) procedure. The procedures for ELOG may comprise
a procedure of molecular beam epitaxy (MBE), metalorganic chemical vapor
deposition (MOCVD) or liquid phase deposition. It is noted that the
buffer layer 22 is configured for improving the quality of the epitaxial
layer 24, the buffer layer 22 may be made of the same material as that of
the carrier board 21 (i.e. disposing the buffer layer 22 is not
necessary) when the lattice constant of the carrier board 21 matches up
with that of the epitaxial layer 24. At Step S15, a first conductivity
type layer 25 is formed on the epitaxial layer 24. At Step S16, an active
layer 26 is formed on the first conductivity type layer 25. At Step S17,
a second conductivity type layer 27 is formed on the active layer 26. The
first conductivity type layer 25 may comprise an n-type III-V
semiconductor material, such as n-GaN; and the second conductivity type
layer 27 comprises a p-type III-V semiconductor material, such as p-GaN.
It is understood that material of the first conductivity type layer 25
and the second conductivity type layer 27 may be exchangeable (i.e. the
first conductivity type layer 25 may comprise a p-type III-V
semiconductor material, and the second conductivity type layer 27 may
comprise an n-type III-V semiconductor material). The active layer 26 may
comprise a single quantum-well structure or a multiple quantum-well
structure and the material and composition thereof may be chosen based on
the wave length of light generated from the quantum-well. The
manufacturing procedures of the first conductivity type layer 25, the
active layer 26 and the second conductivity type layer 27 are similar to
those of producing conventional light emitting diodes; thus, detail
descriptions are omitted herein.

[0028] Continuing the above description, At Step S18, the carrier board 21
is removed, as shown in FIG. 2C, and process of removing the carrier
board 21 can be, but not limited by, means of laser peeling. At Step S19,
a first electrode layer 28 is disposed on the second conductivity type
layer 27 and disposing a second electrode layer 29 below the buffer layer
22, as shown in FIG. 2D. The first electrode layer 28 and the second
electrode layer 29 are electrically connected to the second conductivity
type layer 27 and the buffer layer 22 respectively. The collimating light
emitting device is completed according to the aforementioned steps.

[0029] It is noted that the collimating light emitting device shown in
FIG. 2D is a vertically conducting light emitting device, wherein the
second electrode layer 29 is disposed below the buffer layer 22 and is
configured as an external electrode. It could be understood that the
second electrode layer 29 may be disposed on the first conductivity type
layer 25. Please referring to FIG. 4, FIG. 4 is a schematic diagram
illustrating the collimating light emitting device according to another
embodiment of the present invention. The first electrode layer 28 and the
second electrode layer 29 are disposed on the second conductivity type
layer 27 and the first conductivity type layer 25 respectively, and then
a parallel conducting light emitting device is formed. The manufacturing
process of the parallel conducting light emitting is based on the
structure shown in FIG. 2B, a part of the first conductivity type layer
25 is exposed by means of etching process without removing the carrier
board 21, followed by disposing the first electrode layer 28 and the
second electrode layer 29.

[0030] It is noted that the configuration of the first electrode layer 28
and the second electrode layer 29 is dependent on the configuration of
the patterned optical layer 23. The manufacturing method of the
collimating light emitting device of the present invention is not limited
by the order of the process flow shown in FIG. 1; this means that the
order of the process flow may be rearranged according to process
requirement or the configuration of the patterned optical layer 23, the
first electrode layer 28 and the second electrode layer 29. For example,
the patterned optical layer 23 of the embodiment of the present invention
may comprise a reflective Fresnel optical layer, where the light
generated from the active layer reaches at the 26 the patterned optical
layer 23, the light is collimated upward vertically and emitted to
external environment, wherein the direction is referenced in FIG. 2D. The
second electrode layer 29 may comprise a conducting substrate entirely
covering the lower surface of the buffer layer 22, and the first
electrode layer 28 may comprise a patterned electrode covering a part of
the second conductivity type layer 27, according to the configuration of
the first electrode layer 28 and the second electrode layer 29, it is
known that the collimating light emitting device of the embodiment of the
present invention is a vertically conducting structure, and the patterned
optical layer 23 (reflective Fresnel optical layer) is configured for
collimating light and being able to covert divergent light generated by
the active layer 26 into vertical light.

[0031] Referring to FIG. 5A and FIG. 5B, FIG. 5A is a schematic diagram
illustrating a collimating light emitting device according to another
embodiment of the present invention; FIG. 5B is a schematic diagram
rotating the schematic diagram in FIG. 5A for 180 degrees clockwise for
reference convenience, wherein the patterned optical layer 23 may
comprise a transmissive Fresnel optical layer. The first electrode layer
comprises a conducting substrate entirely covering the second
conductivity type layer 27, and the second electrode layer 29 comprises a
patterned second electrode covering a part of the lower surface of the
buffer layer 22. The patterned optical layer 23 (transmissive Fresnel
optical layer) is configured for collimating light and able to covert
divergent light generated by the active layer 26 into vertical light. The
light generated from the active layer 26 reaches at the patterned optical
layer 23, the light is collimated downward vertically and emitted to
external environment, wherein the direction is referenced in FIG. 5A.

[0032] Referring to FIG. 6 and FIG. 7A to FIG. 7E simultaneously, FIG. 6
is a flow diagram illustrating manufacturing process flow (Step S41
through Step S51) of a collimating light emitting device configured in
array according to an embodiment of the present invention. FIG. 7A to
FIG. 7E are schematic cross-sectional views illustrating the
manufacturing process flow of the collimating light emitting device
configured in array according to the embodiment of the present invention.
Steps S41 to S48 and corresponding schematic cross-sectional view FIG. 7A
to FIG. 7C are the same as Steps S11 to S18 in FIG. 1 and corresponding
schematic cross-sectional view, therefore, detail descriptions are
omitted herein. It is noted that the patterned optical layer 23 in this
embodiment may be a reflective Fresnel optical layer. FIG. 7D corresponds
to Step S49 in FIG. 6, disposing a second electrode layer 29 below the
buffer layer 22 after removing the carrier board 21 (Step S48). The
second electrode layer 29 is electrically connected to the buffer layer
22, wherein the second electrode layer 29 may comprise a conducting
substrate entirely covering the lower surface of the buffer layer 22.

[0033] Continuing the above description, FIG. 7E corresponds to Step S50
to Step S51 in FIG. 6. At Step S50, the second conductivity type layer
27, the active layer 26, the first conductivity type layer 25, the
epitaxial layer 24, the patterned optical layer 23 and the buffer layer
22 are cut through, wherein the second electrode layer 29 is not cut
through so as to form a plurality of units 50 configured in array. At
Step S51, a first electrode layer 28 is disposed, wherein the first
electrode layer 28 comprises a plurality of patterned electrodes disposed
on the second conductivity type layer 27 of each unit 50, wherein the
first electrode layer 28 exposes a part of the second conductivity type
layer 27. The patterned optical layer 23 in this embodiment may comprise
a reflective Fresnel optical layer, and the patterned optical layer 23
configured in array is able to redirect a divergent light to a focusing
light beam in uniform direction without utilizing external lenses thereby
decreasing the size. Besides, the structure shown in FIG. 7E is a light
emitting diode configured in array may be utilized as a micro projection
device having advantages of low power consumption and long lifetime. FIG.
8A is a schematic diagram illustrating a collimating light emitting
device according to another embodiment of the present invention, the
embodiment shown in FIG. 8A further comprises a transparent conducting
layer 60 disposing between the first electrode layer 28 and the second
conductivity type layer 27 for spreading the current evenly to enhance
luminescence efficiency. It is understood that the transparent conductive
layer is selected from a group consisting of IZO, ITO, SnO2,
TiO2, Al2O3, InO and ZnO. Preferably, another embodiment
of the invention further comprises a plurality of insulating layers 70
disposed between the units 50. The insulating layers 70 comprise
insulating materials. The collimating light emitting devices shown in
FIG. 7E and FIG. 8A are vertically conducting light emitting device
configured in array. It could be understood that the collimating light
emitting devices may also comprise a parallel conducting light emitting
device configured in array. Referring to FIG. 8B, FIG. 8B is a schematic
diagram illustrating a collimating light emitting device according to
another embodiment of the present invention, wherein a plurality of
second electrode layers 29 are respectively disposed on the first
conductivity type layer 25 of each unit 50, and a plurality of insulating
layers 70 are disposed between units 50, and a part of the first
electrode layer 28 covers the insulating layer 70.

[0034] It is noted that the manufacturing method of the collimating light
emitting device of the present invention is not limited by the order of
the process flow shown in FIG. 6. As the aforementioned descriptions, the
configuration of the first electrode layer 28 and the second electrode
layer 29 depend on the configuration of the patterned optical layer 23.
Configuration of the first electrode layer 28 and the second electrode
layer 29 and the order of the process flow are changed, when the
patterned optical layer 23 comprises a transmissive Fresnel optical
layer. Referring to FIG. 9 and FIG. 10A to 10B simultaneously, FIG. 9 is
a manufacturing process flow (Step S41 to Step S47 and Step S48' to Step
S51') of a collimating light emitting device according to another
embodiment of the present invention. FIG. 10A and FIG. 10B are schematic
cross-sectional views illustrating the manufacturing process flow of the
collimating light emitting device according to the embodiment of the
present invention. Steps S41 to 47 in FIG. 9 are the same as Steps S41 to
S47 in FIG. 6. FIG. 10A corresponds to Step S48' to Step S49' in FIG. 9,
at Step S48', a first electrode layer 28 is disposed, wherein the first
electrode layer 28 comprises a conducting substrate entirely covering the
second conductivity type layer 27. At Step S49', the carrier board 21 is
removed.

[0035] Continuing the above description, FIG. 10B corresponds to Step S50'
to Step S51' in FIG. 9. Step S50' is cutting through the buffer layer 22,
the patterned optical layer 23, the epitaxial layer 24, the first
conductivity type layer 25, the active layer 26 and the second
conductivity type layer 27 without cutting through the first electrode
layer 28, so as to form a plurality of units 50' configured in array. At
Step S51', the second electrode layer 29 is deposed, wherein the second
electrode layer 29 comprises a plurality of patterned electrodes disposed
below the buffer layer 22 of each unit 50', wherein the second electrode
layer 29 exposes a part of the buffer layer 22. The patterned optical
layer 23 in this embodiment may comprise a transmissive Fresnel optical
layer, and the patterned optical layer 23 configured in array is able to
redirect a divergent light to a focusing light beam in uniform direction
without utilizing external lenses thereby decreasing the size. Besides,
the structure shown in FIG. 10B is a light emitting diode configured in
array may be utilized as a micro projection device having advantages of
low power consumption and long lifetime. FIG. 11 is a schematic diagram
illustrating a collimating light emitting device according to another
embodiment of the present invention, the embodiment shown in FIG. 11
further comprises a transparent conducting layer 60 disposing between the
second electrode layer 29 and the buffer layer 22 for spreading the
current evenly to enhance luminescence efficiency. It is noted that FIG.
11 is a schematic diagram rotating the schematic diagram in FIG. 10B for
180 degrees clockwise for reference convenience.

[0036] Referring to FIGS. 12 and 13, which are simulation diagrams of
light field distribution illustrating the characteristics of the
patterned optical layer (Fresnel optical structure), wherein Appendix 1
represents a simulation diagram of light field distribution of a
conventional light emitting diode (i.e. no patterned optical layer
(Fresnel optical structure) within); Appendix 2 represents a simulation
diagram of light field distribution of a light emitting device with
patterned optical layer (Fresnel optical structure) inside the device. It
is shown that the light field distribution of the light emitting device
with patterned optical layer is more concentrated than that of the
conventional light emitting diode, therefore, the patterned optical layer
(Fresnel optical structure) of the collimating light emitting device of
the present invention has the effect of light collimating.

[0037] In summary, the collimating light emitting device comprises a
patterned optical layer able to redirect divergent light to light beam
with uniform direction thereby having good light collimation. The
patterned optical layer comprises a reflective or a transmissive Fresnel
optical layer. The collimating light emitting device configured in array
may be may be utilized as a micro array projection device without
utilizing external lenses thereby decreasing the size. The manufacturing
methods of the collimating light emitting device are also presented. The
dimension of the collimating light emitting device of the present
invention may be 1 mil to 50 mil depending on the volume of the
projection device, the area or the resolution of the projecting image.

[0038] While the invention is susceptible to various modifications and
alternative forms, a specific example thereof has been shown in the
drawings and is herein described in detail. It is understood, however,
that the invention is not to be limited to the particular form disclosed,
but to the contrary, the invention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope of the
appended claims.

Patent applications by Chen-Yang Huang, Hsinchu TW

Patent applications by Hao-Min Ku, Hsinchu TW

Patent applications by Shiuh Chao, Hsinchu TW

Patent applications in class With shaped contacts or opaque masking

Patent applications in all subclasses With shaped contacts or opaque masking